1. Field of the Invention
The present invention relates to a portable terminal, and more particularly to a hinge device utilized in a portable terminal.
2. Description of the Related Art
Generally, the term “portable terminal” refers to electronic appliances allowing users to make wire/wireless communication with other terminals or base stations while carrying the portable terminals. Such portable terminals may include cellular phones or PDAs.
As wireless communication has been developed, conventional telephone communication has been replaced by wireless communication with many functions, including wireless paging services and wireless character transfer services. Recently, most portable terminals have various functions providing multi-media services, such as image communication services and moving picture transfer services. In addition, as portable terminals have been widely used, consumers have come to demand not only various functions of portable terminals, but also various designs of portable terminals.
Such portable terminals are classified into bar-type portable terminals, flip-type portable terminals, and folder-type portable terminals according to constructions thereof. The bar-type portable terminal has a bar-shaped housing, the flip-type portable terminal has a bar-shaped housing and a flip or a cover rotatably coupled to the bar-shaped housing by means of a hinge device, and the folder-type portable terminal has a bar-shaped housing and a folder foldably coupled to the bar-shaped housing by means of a hinge device.
A current tendency for such portable terminals is to make portable terminals both lightweight and compact to facilitate portability. with folder-type portable terminals, a folder is maintained in a closed position with respect to a phone body in a call wait mode, so that a user can easily carry the folder-type portable terminal. In a communication mode, the folder is rotated to an open position with respect to the phone body so that the user can conveniently communicate with other users.
In addition, a hinge device for rotatably coupling a flip of a flip-type portable terminal or a folder of a folder-type portable terminal to a phone body applies a bias force to the flip or the folder in such a manner that the flip or the folder rotates to a completely opened position with respect to the phone body, if the flip or the folder has been rotated with respect the phone body beyond a predetermined angle, even if external force is not additionally applied to the flip or the folder. The flip or the folder is returned to a closed position with respect to the phone body by means of the hinge device if the flip or the folder is rotated back towards the phone body past the predetermined angle.
One example of such hinge devices is disclosed in U.S. Pat. No. 6,292,980 entitled “Hinge Mechanism Of Portable Phone” and assigned to the assignee of the present invention on Sep. 25, 2001. The hinge mechanism disclosed in U.S. Pat. No. 6,292,980 includes a hinge cam and a hinge shaft having a mountain-shaped portion and a valley-shaped portion, respectively. In addition, a spring is accommodated in a hinge housing in order to closely bias the hinge cam towards the hinge shaft. A folder or a flip is opened or closed with respect to a phone body by means of curved surfaces of the mountain-shaped portion and the valley-shaped portion and the bias force of the spring.
However, according to the above hinge mechanism, the folder is opened or closed with respect to the phone body by simply rotating the folder with one hand while gripping the phone body with the other hand.